What did you learn this summer? Ask Sarah Gray ’11 and she’ll tell you hardwood trees with more nitrate reductase have a better competitive advantage in the forest.

Nitrate reductase is an enzyme found in all plants that metabolize nitrogen. It’s key to Gray’s work at a Harvard University program where her research will contribute to 20 years of data and experience.

The chemistry major is working at Harvard’s outdoor lab in Petersham, Mass., where she is studying species of hardwood trees and their response to soil warming and increased nitrogen levels in the soil due to global climate change.

Harvard Forest is one of 26 long-term ecological research sites in the country. Funded primarily by the National Science Foundation, it focuses on long-term environmental change.

Every day is a new challenge as Gray and her 33 cohorts work both independently and together on field sampling, laboratory studies, data analysis and scientific writing.

Students also contribute to the project’s blog, and attend weekly seminars given by nationally known scientists and workshops on career and graduate-school preparation. Their excursions to explore the local environment have included going on a whale-watching expedition and helping wood turtles in their natural habitat.

At the end of the 12-week program, each student presents his or her work at Harvard Forest’s annual research symposium. They are also encouraged to continue the association with their mentors through the academic year as they seek to publish their research results in scientific papers, honors theses and conference abstracts.

Gray was drawn to the Harvard Forest program for its combination of lab and fieldwork. She spent her spring semester studying abroad, but knew she wanted to join an undergraduate summer research program, so she applied to Harvard Forest from her host university in Ireland.

Gray is hoping the experience will help her decide whether to pursue a career as an environmental chemist or ecologist.